Marfan Syndrome (MFS) is an autosomal dominant disorder caused by mutations of the fibrillin locus on chromosome 15. This connective tissue protein results in multisystem laxity of the extracellular matrix. Case reports and a population based study of obstructive sleep apnea (OSA) in adults with MFS have revealed a prevalence of sleep-disordered of 57%. MFS patients may be at high risk for OSA by cirtue of their highly complaint upper airway or maxillary anomalies. Our protocol aims to determine the prevalence of sleep-disordered breathing in MFS children by obtaining an overnight polysomnogram in an unselected population of children with MFS. To date, we have recruited two children with MFS. Both polysomnograms were normal.